Steel Buildings in Europe

Part 1: Architect’s Guide 1 - 34 6 OVERHEAD CRANES Certain industrial buildings require overhead cranes – examples are printing shops (for moving rolls of paper) and engineering shops (for moving heavy equipment and components). An example is shown in Figure 6.1. Most overhead cranes use single or twin beams spanning across the building and with a hoist mounted on the beams. The crane beams are supported on runway beams that run the length of the building. The crane serves the whole floor by moving along the runway beams and by moving the hoist along the crane beams (Figure 6.2). Incorporating an overhead crane in a building always influences the design of the building structure, even when the hoisting capacity is very modest. A key design consideration is to limit the spread of the columns at the level of the crane. For this reason, portal frames are not appropriate for heavy cranes as limiting the column movement becomes uneconomic. Crane use also results in horizontal forces from movement of the loads, so additional bracing is usually provided. A crane with a lifting capacity up to a safe working load of about 10 tons (100 kN) can usually be carried on runway beams that are supported off the columns that support the roof. For larger cranes, it is more economical to use separate columns (or vertical trusses) to support the runway beams and avoid excessive loads on the building structure. Figure 6.1 Heavy crane in a large industrial building